Skip to main content
Help Center Community Shop

AR 15 CYCLE

DAMMITDON
What can you do to cycle sub sonic amo in AR 15?
0

Comments

10 comments

Date Votes
  • tsr1965
    Nothing...the AR-15 has a fixed size gas port, and is direct impingment. However, if you have a gas piston driven AR, that has an adjustable gas valve on it, you could open it up to allow more gas to hit the piston.

    I don't think the sub-sonic stuff was meant to cycle. I think it was supposed to be a "one shot, one kill" type of deal, and the subsonic was to keep your location stealthy.

    Best
    0
  • nmyers
    I would think that you could shorten the buffer spring. Or, do they sell lighter weight buffer springs? If you have a Class 3 dealer nearby, he may help; he will want to sell you a suppressor as the next step.

    Neal
    0
  • beantownshootah
    quote:Originally posted by tsr1965
    Nothing...the AR-15 has a fixed size gas port, and is direct impingment. However, if you have a gas piston driven AR, that has an adjustable gas valve on it, you could open it up to allow more gas to hit the piston.

    I'm not quite that pessimistic.

    Easiest/cheapest way?

    Buy the 60 grain Aguila SSS .22LR ammo, and drop a .22LR conversion into your AR-15.

    Voila, you get identical ballistics to "true" subsonic .223 Remington, at a fraction of the cost and hassle. Unlike "regular" 40 grain .22LR, the 60 grain SSS ammo is actually stabilized by a typical AR-15 barrel, and can actually deliver good accuracy.

    There probably ARE ways to build/modify an AR-15 to run reliably with subsonic .223 ammo (ie close mounted/pistol length gas tube, light buffer spring, reduced weight bolt carrier group, etc), but this begs the question of why you would actually want to do so.

    Any upper modified this way would probably have to be a dedicated subsonic-only upper, and even a few rounds of "ordinary" .223 might damage/ruin it.

    Meanwhile, as mentioned above, if you're shooting conventional .223 ammo at subsonic velocity, you've basically got a .22LR anyway. So why not just go that route?

    quote:EDIT (responding to below):
    the cmmg drop in conversion units that i use and sell will not reliably work with aguila SSS
    Fair enough. I definitely agree that a dedicated purpose-built .22LR upper is better in just about every way than these drop-in conversions.

    If you already have a drop-in conversion, or are working on a sparse budget, ordinary 40 grain "match" .22 is typically subsonic all by itself.

    You may not get quite the "punch" you will with the 60 grainers, and you probably won't see the same accuracy, but they will be pretty quiet, especially suppressed, and they'll probably run a drop in unit OK.
    0
  • fordsix
    the cmmg drop in conversion units that i use and sell will not reliably work with aguila SSS 62gr tryed all sorts of things as i wanted to use the 1:9 twist in the rifles...but they work flawlessly in a dedicated upper useing CMMG units that have the barrel coller and not a chamber insert were the 22 cartridge goes into the barrel i have since bought a tac sol ruger 10/22 barrel in 1'9 twist just for the 62g sss 22lr and it works great(after a change with a presion made 10/22 extractor)
    0
  • rufe-snow
    You might consider an after market gas block with a user adjustable gas valve. Needless to say the the gas port hole in the barrel would have to be opened up to a larger diameter.


    After the above mods it would be a trial and error type experimentation until hopefully you got the correct amount of gas going to the BCG, so that it would feed and function correctly.
    0
  • Juggernaut
    With some adjustments a heavier grain weight bullet such as the 77gr, 90gr and 100gr should be more likely to cycle the weapon properly in regards to pressure all while remaining subsonic.
    A slower burning powder and softer spring or the spring from a .300 whisper may also help here as well.
    However if using a lighter weight bullet that does cycle the weapon but can remain subsonic must also be stable especially when using a suppressor or you could end up with baffle strikes, so something to watch for before using a suppressor.
    Reportedly with handloads using 62gr or 69gr with 5.6gr of trailboss with a suppressor and softer spring can remain subsonic and stable with this load and with good penetration at distance of up to 100yd.

    Regards
    0
  • armilite
    Check with Brownells seems to me that they offered a somewhat adjustable gas tube for the direct impidgement systems.
    0
  • Juggernaut
    quote:Originally posted by armilite
    Check with Brownells seems to me that they offered a somewhat adjustable gas tube for the direct impidgement systems.


    That is a good idea armilite and may also work as well and I think that you are referring to these:

    http://www.brownells.com/.aspx/pid=42746/Product/AR-15-ADJUSTABLE-LOW-PROFILE-GAS-BLOCK

    http://www.brownells.com/.aspx/pid=53466/Product/AR-15-AR10-FRONT-ADJUSTABLE-GAS-BLOCK

    Regards
    0
  • armilite
    quote:Originally posted by Juggernaut
    quote:Originally posted by armilite
    Check with Brownells seems to me that they offered a somewhat adjustable gas tube for the direct impidgement systems.


    That is a good idea armilite and may also work as well and I think that you are referring to these:

    http://www.brownells.com/.aspx/pid=42746/Product/AR-15-ADJUSTABLE-LOW-PROFILE-GAS-BLOCK

    http://www.brownells.com/.aspx/pid=53466/Product/AR-15-AR10-FRONT-ADJUSTABLE-GAS-BLOCK

    Regards


    I thought so, I replied to this early in the morning before going to work and really didn't have any time to check it out more thoroughly.
    I seemed to remember them sending me an email some time back as to them being available as a new product.
    0
  • Juggernaut
    quote:Originally posted by armilite
    quote:Originally posted by Juggernaut
    quote:Originally posted by armilite
    Check with Brownells seems to me that they offered a somewhat adjustable gas tube for the direct impidgement systems.

    That is a good idea armilite and may also work as well and I think that you are referring to these:
    http://www.brownells.com/.aspx/pid=42746/Product/AR-15-ADJUSTABLE-LOW-PROFILE-GAS-BLOCK
    http://www.brownells.com/.aspx/pid=53466/Product/AR-15-AR10-FRONT-ADJUSTABLE-GAS-BLOCK
    Regards

    I thought so, I replied to this early in the morning before going to work and really didn't have any time to check it out more thoroughly.
    I seemed to remember them sending me an email some time back as to them being available as a new product.

    That along with most of the other helpful suggestions will be more than enough to take care of any subsonic ammunition uses with AR15 rifles and despite misinformation.

    Regards
    0

Please sign in to leave a comment.

Recent Activity

Didn’t find what you’re looking for?